The present invention relates to a cantilever unit suitable for a scanning atomic force microscope (AFM) which is a typical scanning probe microscope, and more particularly to a cantilever unit having a self-detecting type cantilever outputting an electric signal in response to deflection of the cantilever itself.
In the scanning atomic force microscope (AFM), a cantilever having an exploring needle at a free end is used as a scanning probe. In the configuration, because attraction or repulsion based on interatomic force appears between surface of a sample and the exploring needle by scanning the exploring needle on the surface of the sample, a shape of the surface of the sample can be measured by detecting the interatomic force a as deflection of the cantilever.
Although deflection of said cantilever is measured by detecting an optically displacement quantity of a reflecting beam radiated to a back surface of the cantilever, there is a problem that the configuration is complex and adjusting is difficult in the way detecting optically deflection of the cantilever. Therefore, a self-detecting type cantilever is developed recently which directly outputs detected deflection as electric signal forming a detecting circuit for detecting deflection on the cantilever.
The self-detecting type cantilever having the above-mentioned configuration is installed on the main body of the microscope as a cantilever unit in the detachable state holding the cantilever on the surface of semiconductor substrate in cantilever type because it is difficult to handle alone.
In the scanning probe microscope, there are various modes except the above-mentioned AFM mode. They are a friction force microscope (FFM) mode detecting change of friction applied between surface of sample and cantilever as deflection of horizontal direction of the cantilever, a magnetic force microscope (MFM) mode measuring magnetic distribution of surface of sample detecting magnetic force by AC detecting method making an exploring needle magnetized and cantilever resonate, and a tunnel microscope mode measuring surface shape by applying voltage between surface of sample and cantilever, and by controlling and detecting tunnel current flowing through between them.
In any of operation modes, an exclusive cantilever unit can be selectively installed without changing the main body of the device. Therefore, an operator should selectively install a cantilever unit corresponding to the desired operation mode on the main body of the device.
Here, it is difficult to identify each cantilever unit with the naked eye because the cantilever units are not very small in size but also are little difference in their constructions though shape and size of the cantilever portion is different from each other depending on their kinds. Therefore, it has been difficult to identify the desired cantilever unit when the cantilever unit suitable for the desired operation mode is searched among the stock. It has been difficult to identify too the cantilever unit being installed now on the main body of the device.
An object of the present invention is to provide a cantilever unit enable to identify simply kinds of cantilever units with eyes solving the conventional above-mentioned problem.